in the picture you can see the electric circuit. i asked to find the current in R3. i mark 4 circle (a b c d) and i got the 4 equations (shown in blue color). in equation C, i not sure if is equal to 100 or to 0, but i tried with both of them. after i found this equations i used this calculator:http://wims.unice.fr/wims/wims.cgi?session=YCB515D978.2&+lang=en&+module=tool/linear/linsolver.en to get the 4 variable. but for some reason i am not get the correct answer is should be 6.666A. what i do wrong? thanks.